Persistent post-surgical pain (PPSP) and impaired functioning are common among patients undergoing total knee arthroscopy (TKA). Pain that persists beyond the expected period of healing can be devastating to one's sense of well-being. In fact, pain severity is highly correlated with adverse effects on physical functioning. Strong and consistent evidence indicates that patients with high anxiety and/or depressive symptoms (distress) prior to surgery are at risk for PPSP. Veterans are at particularly high risk for post-surgical problems because 80% experience some level of psychological distress prior to surgery and 50% report experiencing pain on a regular basis. Scheduled surgery is a critical juncture with the healthcare system that provides an important opportunity to identify and address these issues. Acceptance and Commitment Therapy (ACT) is a trans- diagnostic and evidence-based treatment for depression, anxiety, and chronic pain. Importantly, ACT has been effectively implemented in various treatment-delivery formats, including intensive 1-day group workshops. This application proposes a multi-site, double-blind, two-arm, parallel, randomized controlled trial comparing the effects of an ACT intervention to an attention control (AC) intervention in Veterans at-risk for PPSP following TKA. Veterans with high levels of pain and significant distress prior to TKA will be identified as ?at-risk.? The primary aim of this study is to examine the efficacy of ACT compared to AC on pain and functioning in at-risk Veterans at 6 weeks, 3 and 6 months post-TKA. The secondary aim is to examine the effects of ACT, compared to AC, on depressive and anxiety symptoms and on coping skills. Mediation analyses will be conducted to examine whether changes in depression, anxiety, and coping skills have an impact on pain and functioning. Finally, we will explore the impact of the current opioid restrictions on the use of pharmacological and non-pharmacological pain management strategies following TKA. The current proposal builds on promising results from a R34-funded preliminary study. Providing this therapy prior to surgery for people struggling with depressive and anxiety symptoms, for the purpose of preventing PPSP and impaired functioning following surgery, is innovative. It has the potential to change clinical practice from a focus on management of postoperative pain to prevention of chronic pain in at- risk individuals. This project incorporates an interdisciplinary approach to the care of Veterans that attends to major risk factors of postoperative sequelae that significantly impact Veterans' quality of life and healthcare utilization. Thus, it has the potential to translate what is known about effective treatments of distress and chronic pain to prevent poor surgical outcomes. The format is brief and innovative, offering potential for optimal treatment adherence, participant acceptability, and broad deployment to practice settings. Finally, this more concentrated and time-limited approach allows for completion within a short window of time, such as before surgery.